The present invention relates, in general to dielectrics used in manufacturing electronics, and more particularly to spin-on dielectrics for use in manufacturing semiconductors.
The use of spin-on dielectrics had previously been used in the semiconductor industry in the form of spin-on glass. These uses of spin-on glass was well known in the art of semiconductor processing. Spin-on glasses typically were made from organosilicon compounds and water, and were dissolved in an alcohol medium. The resulting polymers, called siloxanes, were liquids that could be applied to semiconductor wafers, spun to form a uniform coating, and cured to form an adhesive bond to a desired substrate. During curing, the siloxane polymer adhered to the substrate by forming a silicon-oxygen bond that was a glass. Consequently, they were called spin-on glass and were primarily used as dielectric materials. These previous spin-on glasses were limited by their high dielectric constant. When used to insulate conductors on a semiconductor chip, the high dielectric constant of these spin-on glasses produced capacitive loads on these conductors which degraded the performance of both high frequency and high density transistors. With semiconductor technology continually producing smaller transistors with correspondingly smaller output drive for these capacitive loads, the performance of transistors was degraded by the capacitance of spin-on glasses. Previous spin-on glasses had dielectric constants in excess of 3.8. Those with dielectric constants in the 3.8 range compared closely to silicon dioxide (approximately 3.9) but were still higher than other dielectrics such as polyimide (2.8-3.5) and, in extreme high frequency applications, air (1.0). Consequently these spin-on glasses were not suitable for use as a dielectric in many semiconductor applications.
Accordingly, it would be desirable to have a spin-on dielectric having a low dielectric constant.